Said Gary Small, who led the study: 'This suggests that we may now have a new diagnostic tool for detecting pre-Alzheimer's conditions to help us identify those at risk, perhaps years before symptoms become obvious.

By IANS, [RxPG] New York, Dec 27 - Scientists in the US claim to have developed an advanced scan technique that can spot early symptoms of Alzheimer's disease.

According to researchers, Alzheimer's disease is strongly linked to the appearance of abnormal areas called 'amyloid plaques' and 'tangles' in the brain although the precise role of these is not fully understood.

These areas do not show up using conventional Magnetic reasoning imaging - or Computed Tomography - scanning and are visible only during autopsy.

Alzheimer's disease is a progressive brain disorder that gradually destroys a person's memory and ability to learn reason and make judgments.

Although the disease can be diagnosed by assessing mental decline, physical changes within the brain can usually be confirmed only by a post-mortem.

A team at the University of California claims to have invented a chemical that not only shows up on scans but will bind to plaques and tangles, reported the online edition of BBC News. Using another scanner called Positron Emitting Tomography -, the damaged areas show up clearly.

The researchers studied over 80 people - some of them healthy, some with mild cognitive impairments such as memory loss and 25 who were diagnosed with Alzheimer's because their symptoms were more advanced.

After being injected with the chemical, they were scanned to see if there were any differences between the groups.

The levels of the chemical appearing on the scans were much higher among the Alzheimer's patients compared with the others. The technique also highlighted more subtle differences between the healthy volunteers and those with mild symptoms.

Said Gary Small, who led the study: 'This suggests that we may now have a new diagnostic tool for detecting pre-Alzheimer's conditions to help us identify those at risk, perhaps years before symptoms become obvious.

'This imaging technology may also allow us to test novel drug therapies and manage disease progression over time, possibly protecting the brain before damage occurs.'